This application relates generally to monitoring gas turbine engine debris, and more particularly, to detecting debris using different debris sensors.
Gas turbine engines are known and typically include multiple sections, such as a fan section, a compression section, a combustor section, a turbine section, and an exhaust nozzle section. During stable operation, the fan section moves air into the engine. The air is compressed as the air flows through the compression section. The compressed air is then mixed with fuel and combusted in the combustor section. Products of the combustion expand to rotatably drive the engine.
Gas turbine engines operate in various environments. Some environments include debris, such as sand and stones, which can move into the engine with the air. As known, debris can undesirably accelerate wear and erosion of the engine's components. Engines often utilize inlet debris monitoring systems to detect and monitor particles of debris entering the engine. Other types of debris monitoring systems monitor debris in other areas of the engine, For example, an exit debris monitoring system monitors debris exiting areas of the engine. These systems typically include one or more debris sensors within or in front of the fan section of the engine. The debris sensors detect debris entering the engine by sensing the electrostatic charge of debris. The inlet debris monitoring system compiles the detection information for monitoring purposes as is known art.
The sensitivity of the debris sensors to the electrostatic charges of the debris depends in part on the size and exposed surface of the debris sensor. For example, smaller diameter ringed debris sensors are more sensitive to electrostatic charges than larger diameter ringed debris sensors, and axially wider ringed debris sensors are more sensitive to electrostatic charges than axially narrower ringed debris sensors. Button type sensors are another example type of debris sensor. Using debris sensors that are too sensitive, or sensors that are not sensitive enough, can complicate distinguishing electrostatic charges of the debris from other electrostatic charges. Example complications include signal saturation, which could result from using sensors having large sensor surfacing areas to detect large amounts of dense particulate, such as a cloud of sand or water.
In the prior art, each debris sensor communicates with a signal conditioning unit dedicated to that debris sensor. That is, the number of signal condition units is the same as the number of debris sensors, which presents a bulky and complex arrangement. After detecting an electrostatic charge from debris, the debris sensor communicates a signal to the signal conditioning unit, which filters and digitizes the signal. The filtered and digitized signals are provided to the inlet debris monitoring system, which can then determine the quantity and rate of debris entering the engine.